I found a way by accident. I was home dyeing my hair and I accidentally mixed the conditioner with the fluid, rather than the colour with the fluid.
I had it on for about 5 minutes before I realised my mistake.
My hair had been dry, frizzy and with split ends for 12 months by then, and I could never seem to cut it short enough to get rid of the split ends. However, that accident sorted it out for good.
That was ages ago and it's still soft now.